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| Ask the Experts |
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June 4, 2006 - Updated
July 5, 2007 - Originally Posted
Preferred PCB finish between ENIG and immersion silver?
With the advent of lead free SMT and THT processing requiring elevated process temperatures for soldering, is there a preferred PCB finish between ENIG and immersion silver?
B.H.
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| Expert Panel Responses |
Both finishes have a plus and minus. ENIG has a history already, stores very well and in general works well until the dreaded black pad appears. However this is less of an issue than it use to be, but when it does occur it can be a problem. In general cost is slightly higher for the ENIG but not always volume and purchasing play a role in the pricing.
Silver immersion is also a good finish, however it does not store well, silver is very sensitive to sulfur in the air so in some areas it can be a problem. If you do not have high turn over or proper storage the silver can be a problem.
It really comes down to company preference and capabilities to handle the different material.
Karl Seelig
Deck Street Consultants
In his 32 years of industry experience, Mr. Seelig has authored over 30 published articles on topics including lead-free assembly, no-clean technology, and process optimization. Karl holds numerous patents, including four for lead-free solder alloys, and was a key developer of no-clean technology.
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